Aerodynamic stabilizer



J. V. MARTIN.

AERODYNAMIC STABILIZER.

APPLICATION FILED MAY 11, 1916.

Patented Mar. 23, 1920.

r 3 SHEETS-SHEET 2.

W! mm -L V. MARTIN.

AERODYNAMIC STABILIZIEIL APPLICATION FILED MAY n Patented Mar. 23, 1920.

3 SHEETS-SHEET 3.

FIG. 10.

FIG. 7.

gluon: T01: %17'666' Ell [arm -place the vertical or of my device insuch position relative to the JAMES Vx l llillt'llll', F DETROIT,MICHIGAN.

annonrnaivric sranrmznnj narrator.

To all whom it may concern:

Be it known that-l, JAMES V. MARTIN, a citizen of the United States ofAmerica, residing at Detroit, in vthe county of Wayne and State ofMichigan, have invented certain new and useful Improvements inAerodynamic Stabilizers, of which the following is a specification,reference being hadtherein to the accompanying drawings.

My invention aims primarily to provide curve of the machines progressionat sub sta-ntially the center of pressure and thus prevent skidding. v

lit is a further, object of my invention to provide .an aerofoil sectionwhich creates practically the same lift and drift 'coefii-- cients atsmall positive angles of incidence as it does at the correspondingnegative an les of incidence.

t is a further object of my invention to anti-skidding aerofoil aircraftthat it is free from interference i of fuselage, propellers, motors,struts and the-like and Where it will be readily influenced by theoblique airs local to one or both extremities of'the air craft.

, it is a further object of my invention to eliminate so far aspossible, the friction of operating parts in order that the inception ofinsensible oblique airs shall operate the mechanism and thus anticipateand counteract deflection of the aircraft from the normal.

operating connection between Specification of LettersPatent. PatentedMarat, 192d. Application filed May 11, 1916. Serial 'No. 96,749.

described as attached to the wing of an aeroplane although it may bereadily adapted to any sort of self-propelled'air craft. By slightalteration the device may be made to provide for longitudinal as well aslateral automatic control.

The invention consists in the matters hereinafter set forth, and moreparticularly pointed out in the appended claims.

In the drawings,

Figure 1 is a diagrammatic plan view of an air craft equipped withstabilizers embodying features of the invention;

Fig. 2 is a viewin front elevation thereof:

Fig. 3 is a view in detail of a stabilizer and adjacent end portion ofan aeroplane wing; I L

Fig. 4 is a plan view thereof; and

Fig. 5 is a view in detail of one form of the parts of the device.

Fig. (Sis a side elevation of an aeroplane illustrating the adaptationof the device to 1 automatic'longitudinal control.

Fig. 7 is an enlarged side elevation of the device partially broken awaytaken substantially upon line 77 of Fig. 9.

Fig. 8 is a top plan view of the same.

Fig. 9 is an enlarged top plan View of a central portion of the device,and,

Fig. 10 is an enlarged sectional view taken upon line X-X of Fig. 7.

In the drawings, each extremity of an aeroplane of well known type, isprovided with a member 1 extending from the end portion of the mainplane 2 or other suitable part of the machine to which it is securelyanchored. An aerofoil 3 of any wing section, but preferably of a designwhich creates equal head resistance, at similar but opposite angles, issupported tiltably on the member 1, preferably by ball bearing col larsor the like, this axis of motion being located'at or near the maincenter of pressure of .theaerofoil for positive and negative angles ofincidence through a range substantially of from. zero to about sixteendegrees in either direction. Preferably also the axis of oscillation ofthe aerofoil 3 passes through the center of gravity of the aerofoil atthough this is not an essential requirement. Attention is called to theshin contour of aerofoil 3 as an important feature of my in vention; ithas practically the same curvature on both its conveirslrins. 11o

The efficiency and dependability claimed for this device result from itsentreme sim plicity and from the utilization of forces al ready involvedin aeroplane flight without the. assistance of motors, springs or gyroscope, I

Tlhe device may be described briefly as an aerodynamic stabiliserconsisting of two movable parts, a stab-iliser being fitted to eachlateral extremity of the air craft.

The stabilizer is herein illustrated and .A normally upright arm 5 isjournaled on the machine in convenient proximity to the member 1, insuch manner as to swing freely ina plane parallel to the member 1 and 5consequently transversely to the axis of oscillation of the plane 3. Apendulum weight 6 having aystream line contour or conformation isattached rigidly to the lower portion of the member 5, the latterpassing 10 upwardly through the skin of the main plane .of themachine,-or at any rate above the latter to afford-support to' anupright aerofoil 7 that is mounted on the member 5 in a planesubstantially parallel with the longitudinal axis of the machine.

The member 5 and the auxiliary frame or aerofoil 3 are interconnected insuch manner that the outward movement of the pendulum .6 causes theforward margin of the frame'3 to rise and a reverse motion of thependulum causes the forward margin to lower. As herein shown, suchinteroonnec tion may consist of a segmental gear 8 carried by the arm 5in mesh with a segmental pinion!) that is secured to the journal portion10 of the plane 3. It is to be understood that the disposition of theseinterconnecting parts is in Consonance with good mechanical constructionand practice, the important feature being the location of the member 5at the wing extremity in direct connection' with aerofoil 3, thuseliminating the friction of leafds and permitting aerofoil 7- to beinfluenced by the oblique relative airs local to one wing, and removingaerofoil 7 from pcsltlons near the center of the aeroplane where itsusefulness would be ruined by the Y air interference caused. byfuselage, motors, propellers, struts and the like. 40 It is alsoimportant to note that aerofoil 3 is supported on member 1 by bearingsdisposed within it, this being a great improvement over former practicesince the bearmgs thus disposed take pressure evenly and do not bindasaresult of wind pressure on aerofoil 3. 1

Itis also to be noted that the upright -aerofoil 7 is secured to themember 5 in such manner as to be supported at substantially its centerof pressure. This center of pressure, is prevented from shiftingto anyappreciableextent by the shape of the skin surfaces of the ailerons,both of which are cambered, or the aerofoil'may be said to bedouble-cambered. This contour is better than any other wing section, inthat the movement of the center ofi pressurev is less than one-half thatof other and standard sections. Furthermore itenables the housing of themember 5' which is cdmpletely and fully inclosed and therefore reducesthe skin'resistance of the aeroplane in flight. With both extremitiesofthe aeroplane equ pped in this way, should the aeroplane deviateduringflight from the lateral horizontal plane in however slight adegree, the weight 6, which acts freely under the influenc'e of gravityand centrifugal force save for the friction of theauxiliary plane on itsbearing, will cause the auxiliary plane that 0 aeroplane.

Should the aeroplane become tilted and have a considerable lateralinclination so that it increases its speed in the direction of itsinclination, then the upright aerofoils 7 will by the action of the airimpinging on the surfaces thereof, accentuate the action of the weights6 already communicated to the planes on the lower wing and high wingrespectively.

Should the aeroplane be laterally horizontal in flight, and the steeringrudder be operated to turn the aeroplane from its straight course, thependulum weights 6 will tend to continue their motion in the originalline of flight and will both swing toward that end of the plane whichwould describe the largest circle. This would cause the auxiliaryaerofoil on the outer circle to take a larger angle of incidence and toconsequently raise the outer wings, and the one on smaller or shortercircle, to take a negative angle and depress the inner wing. This isequivalent to banking the aeroplane for a turn, thus effectingautomatically to a large degree the necessary operation of the plane insuccessful flight. -Any skidding tend- Obviously, changes in the detailsof construction may be made without departing from the spirit of myinvention and I do not care to limit myself to any particular form orarrangement of parts.

The adaptation of the device to the automatic maintenance of theaeroplanes longitudmal balance is illustrated in Figs. 6 to 10 bothinclusive of the drawings, and will i be briefly described.

The aeroplane illustrated in Fig. 6 is provided with main planes 2'while the empennage comprises a mounting member 1 supported by outer andinnerbrackets 11 and 12 respectively, while a horizontal rudder 3 istiltably arranged upon the support 1, having a cut-away portion 13arranged withthe transverse hub 10', the said hub and rudder beingjournaled upon the support 1', An upright rod or arm 5 is journaled at apoint above its center of gravinset/or ity within the cut-away portion13 upon the ends of the inner brackets 12 and is provided with apendulum weight 6' at its lower end while an aerotoil 7 is rearwardlycarried horizontally by the arm 5. The arm 5 is of stream lineconstruction as indicated by the cross-sectional view, Fig. 10,whilecotiperat ing segmental gears 8 and 9 are respectively, arrangedupon .the arm 5 and the hub 10. The operation of the longitudinalstabilizer just described, will be apparent from the foregoingspecification, the diving ot the aeroplane automatically resulting 1n anegative incidence on aerofoil 7 depressing the latter and causing anegative incldence in rudder 3 while an ascending movement of theaeroplane will create a positive incidence on aeroitoil 7 which willresult in a positive incidence .on the rudder 3 which will raiseemennage until the aeroplane is again preceeing normally.

My invention includes means for ut lizing variation in the direction andvelocity of the air currents local to the wing to control the lateralbalance ofthe aeroplane. Such conditions are called relative airs,meaning any change of the direction of the air from the normal, where agiven incidence is assumed as normal." These difi'erent conditions aresix in number, viz

1. Increased speed of air,

2. Decreased speed of air, 3 Up currents ofair,

Down currents of air, Right oblique airs,

6. Left ob lique airs.

I claim as my invention:

1. In self-propelled air craft, end plane or planes .tiltably mountedapproximately on their combined centers of pressure and gravity topresent both positive and negative angles between zero and substantiallysixteen degrees, and automatic means for controlling the angle of theend planes to return the air craft to the horizontal, including apendulum and coiiperating aerofoil. N

2. In combination with an aeroplane, two

independent stability devices oppositely dis posed but actingconjointly, one on the right and one on the left lateral extremity ofthe aeroplane, including independent pendulums and vertical aerotoils tooperate the devices to depress the high wingand raiscthe low wing,

ln combination with aeroplane err-- tremities. a pendulum rod on eachextremity connected with a tiltable aileron, and pro vided with anextension above its pivot cein ter, and a vertical aeroloil on extensionto accentuate the action elf the pendulum. in. maintaining the aeroplaneslateral normal. balance by altering the incidence oi": the aileron, I

t, In an aircra'tt, a pendulum rod on the lateral extremity thereothaving an aerol oil on the upper end thereof above the pivot,operatively connected with an aileron to maintain the aeroplanes lateralbalance.

5. In an aeroplane, an aileron at each latrudder, the said rod beingpivoted at a point above its center of gravity.

7. In an aeroplane, a pendulum rod at the lateral wing extremity thereofpivoted to swin on an axis approximately parallel to the line of flight,a vertical aerotoil upon said rod, an aileron journaled to tilt about asupporting arm disposed within the aileron and operative connectionsbetween the said; rod and aileron. v

'8. In combination with the wing extremity of an aeroplane and locatedin proximity thereto, an aileron pivoted on a transverse axis, anormally vertical rod pivoted to swing on a fore and att axis, anaerofoil disposed on said rod, and operating connections .between thesaid rod and aileron.

9. In" combination with an aeroplane wing extremity, an arm rigid withthe wing with an extension 0t said arm arranged beyond said wingextremity, and an aileron inclosing said arm extension as the aileronssupporting axis.

10. In an aeroplane, an aileron disposed laterally beyond the aeroplanewing extremity, a journaled portion rigid with said aileron, and asupporting axis tor the aileron rigid with the aeroplane wing dispost dwithin said journaled portion ot the aileron.

II. In combination with the wing extremity of an aeroplane and locatedin proximity thereto, a pivoted and normally vertical rod provided aboveits pivot point withian aerotoil, an aileron and operative connectionbetween said rod and said aileron to maintain the aeroplane in lateralbalance.

lfilln an aeroplane, an aileron. disposed laterally beyond the aeroplanewing err-- ldtl l ll ll tremity, a horizontal aileron"journaled uponsaid axis, a normally vertical rod pivoted adjacent said axis, avertical aerofoil upon said rod and operative connections upon said rodand alleron whereby the. aeroplane 1s adapted formaintenance in normallateral balance. 1 p 1 14. In comb1nat1on with an aeroplane wlng, adouble convex symmetrical aileron rupon the extremity of the wing, apendulum rod swingin ly mounted upon 'an axial point inclosed wit in thesaid wing and operative connections between said rod and aileron. 15. Incombination, a double convex symmetrical aileron, a pendulum rodoperatively connected thereto, and a weight at the lower extremity ofsaid pendulum rod.

v16. An aileron pivoted on a transverse axis, a normally vertical rodpivoted 3 to swing on a fore-and-aft axis, an aerofoil disposed on saidrod, and parts rigid with said rod engaging parts rigid with saidaileron to operate the said aileron.

forward of its leading edge that its center ofgravity is substantiallycoincident with its center of pressure and pivotal support throughoutsmall angles of incidence thereof, and means for effecting a change inthe, incidence of said aerofoil.

19. In anaeroplane, a double-convex aerofoil weighted at or near itsleading edge so 'as to place its center of gravity and its center ofpressure approximately at its axis of J I support, and means forautomatically effeeting a-change in the incidence of said aerofoll.

20. In an aeroplane, an aileron, a pivotally. supported and weighted armopera-. tively connected to said aileron to turn the same upon swingingmovement of said arm, a vertlcal aerofoil on a portion of said arm aboveits axls of support, and a weight at or i 1 forward of the leading edgeof said aileron to maintain its center of gravity at the axis v of theaileron support.

21. In an aeroplane, pivotally supported ailerons, and automatic meanspivotally supported adjacent the pivotal support of said ailerons foroperating said ailerons to maintain lateral balance, said ailerons beingeach weighted forwardly of its supporting axis and the axis of saidautomatic means to 1 place the center of gravity of said stabilizingone-third the distance of its cord from the leading edge of the aileron.

24. An aileron of varying camber having symmetrical upper and lowerskins with its center of pressure for small angles of incidence and itsaxis of support at its greatest camber.

25. A double convex synmnetrical aileron, having a substantiallyconstant center of pressure at small incidence and its axis of supportapproximately coincident with said center of pressure. p

26. In combination with an aeroplane wing extremity, a normally verticalrod carried by the wing and adapted for lateral movement, and a winginfluencing fin provided on the rod exteriorly of the skin of said wingextremity.

27. In combination with the wing extremity of an aeroplane, a normallyvertical rod pivoted on the wing free to swing-in at least onedirection, a shape of stream-line contour provided on the lower portionof the rod and a wing influencing fin on the upper portion of the rod.

28. In combination with the wing extremity of an aeroplane, a doubleconvex symmetrical fin supported at the wing extremity inclosing itssupport at approximately its center of pressure, an aileron supported atthe wing extremity, and operative connections between the said fin andaileron to alter the incidence of the aileron.

In testimony whereof I aflix my signature in presence of two witnesses.

"JAIMES V. MARTIN.

lVitnesses:

C. R. STICKNEY, AN vA M. DORR.

